Foundries belong to those industrial plants which emit dust and gaseous pollutants to the atmosphere, to ground water and to water reservoirs. Gases are produced during casting. In the foundry the main source of toxic gases are moulding and core sands which emit most of the gaseous pollutants during casting and filing a foundry mould with casting alloy. The author summarizes the results of the studies carried out in the Institute of General Chemistry and Department of the Moulding Materials in the Foundry Faculty of the Cracow Academy of Mining and Metallurgy on properties and quantities of gases emitted by various types of moulding and core sands during casting and filling with liquid cast iron.